Table 2.
Comparison of mean of PRISMA for abstracts items reported in abstracts of meta-analyses of RCT
| Variables | N | Univariable analysisa | Multivariable analysisb | ||||
|---|---|---|---|---|---|---|---|
| Means (standard deviation) | Mean difference (95 % CI) | p value | Adjusted means (95 % CI) | Adjusted mean difference (95 % CI) | p value | ||
| Year | |||||||
| - 2012 (ref) | 84 | 6.7 (1.6) | 7.0 (6.5; 7.5) | <0.001* | |||
| - 2014 | 59 | 6.8 (1.6) | 0.1 (−0.4; 0.7) | 0.694 | 6.9 (6.4; 7.4) | −0.1 (−0.6; 0.4) | 0.711** |
| - 2015 | 61 | 7.5 (1.6) | 0.8 (0.2; 1.3) | 0.007 | 7.8 (7.4; 8.3) | 0.9 (0.4; 1.3) | 0.001*** |
| Abstract word count | |||||||
| - <300 (ref) | 30 | 8.3 (2.0) | 6.9 (6.3; 7.4) | ||||
| - ≥300 | 113 | 6.7 (1.4) | −0.3 (−1.3; −1.0) | <0.001 | 7.6 (6.8; 8.4) | 0.7 (−0.4; 1.8) | 0.184 |
| PRISMA endorsement | |||||||
| - Non endorser journals (ref) | 43 | 7.9 (1.9) | 7.7 (7.1; 8.2) | ||||
| - Endorser journals | 100 | 6.6 (1.4) | −1.3 (−1.9; −0.7) | <0.001 | 6.8 (6.2; 7.4) | −0.8 (−1.7; 0.04) | 0.063 |
| Abstract format | |||||||
| - IMRAD (ref) | 47 | 6.4 (1.6) | 6.9 (6.3; 7.4) | ||||
| - 8-headings | 96 | 7.3 (1.6) | 0.8 (0.4; 1.3) | <0.001 | 7.6 (7.2; 8.0) | 0.7 (0.2; 1.2) | 0.008 |
| Publication on behalf of a group | |||||||
| - No (ref) | 131 | 7.0 (1.7) | 7.3 (7.0; 7.7) | ||||
| - Yes | 12 | 6.7 (1.4) | −0.3 (−1.1; 0.4) | 0.394 | 7.1 (6.5; 7.8) | −0.2 (−0.8; 0.5) | 0.557 |
| Number of authors | |||||||
| - ≤6 (ref) | 64 | 6.9 (1.6) | 0.1 (−0.4; 0.6) | 0.659 | 7.2 (6.7; 7.6) | ||
| - >6 | 79 | 7.0 (1.7) | 7.3 (6.9; 7.7) | 0.2 (−0.3; 0.6) | 0.464 | ||
Ref reference for mean difference calculation, PRISMA preferred reporting items for systematic review and meta-analysis, IMRAD introduction, methods, results, and discussion
aStudent’s t test, *Global p value
bGeneralized estimation equations with journals as grouping variable. Goodness of Fit: value of the Corrected Quasi-likelihood under Independence Model Criterion = 1827.12 and the value of the Quasi-likelihood under Independence Model Criterion = 1829.28
After Bonferroni correction for multiple comparisons, values are **1.0 and *** 0.002